3 9. The legal doctrine of the Inter-American Court concerning preventive detention (which includes and clarifies the prevailing standards in this regard in accordance with the circumstances of this hemisphere), is based on several principles that should be recalled and on which it is necessary to insist in order to contain and reduce the tendency to carry to extremes the hypotheses for precautionary deprivation of liberty. It is evident that, under the rule of law, any deprivation of liberty – detention, preventive or precautionary detention, educational or therapeutic internment, administrative or criminal sanction – should be clearly established by law, with moderation and precision. Thus, in this regard, there is a space for the “legal reservation,” the principle of legality strictly speaking (formal and substantive law: concepts that the case law of the Inter-American Court has also developed), which precludes authoritarian discretion, as well as lesser norms that are not enveloped in the guarantees that a real law requires: administrative and regulatory provisions; “autonomous” regulations, whose issue depends on regulatory authorities, which determine the hypotheses for deprivation of liberty – the offenses – the corresponding consequences and the procedures for applying the latter. 10. The paramount rule of minimum penal intervention – which has special implications in the matter that I am now examining – leads to reducing the hypotheses for precautionary deprivation of liberty to their minimum expression: not the most, but the least; not the system or the rule, but the exception. This would lead to a deliberate re-formulation of the law to elucidate the space currently occupied by preventive detention. According to case law, this objective is interrelated with the decision that preventive detention is only contemplated when it is truly necessary. However, we can require more – as has been required at times: that it is only contemplated when it is essential. 11. Obviously, the condition of being necessary or “essential” is not left to the whim of the authority or of public opinion, which could characterize as necessary or essential a measure that, in reality, is unnecessary or can be substituted. To comply with the obligation to respect and ensure human rights, the State must organize the public apparatus to this end, using all possible means, with the broadest – not the most restrained or most modest – application of available resources. The same is true as regards the liberty or control of the accused, the development of the investigation, and the preservation of the evidence during the criminal proceedings. Consequently, the State must use as frequently as possible – which is often – precautionary measures other than deprivation of liberty. Is this easy? Is this inexpensive? Perhaps not; but nor is preventive detention simple or economical and, in addition, it is founded on a delicate compromise – a complex transaction – between justice and necessity, which functions in an unstable equilibrium. 12. Preventive detention, I have reiterated, is a precautionary measure; it serves the immediate purposes of the trial; it caters to the latter’s most urgent needs; it allows the trial to evolve and conclude in reasonable terms and the judgment to be executed, not evaded. Even though it evidently entails oppressive force, it should not acquire this quality formally: it should not constitute a penal measure or punishment that imposes on the individual the loss or the violation of a fundamental right to respond to other, often remote, purposes of the proceedings against him. Thus, it obeys urgent and immediate procedural requirements, namely: the effective subjection of the accused to the proceedings against him and their satisfactory evolution – the undesirable alternative is a trial in absentia, which gives rise to another set of problems. Obviously, both factors for the deprivation of liberty must be sufficiently established; the accuser’s allegations or the superficial impression of the judge are not sufficient. It is necessary to prove the real risk that the accused will escape justice and the danger, also real, for the normal evolution of the proceedings. Deprivation of liberty restricts a fundamental right; this is why it must be duly motivated and founded.